As expiration looms, bulls scoop up DNDN's weekly calls

Dendreon Corporation (NASDAQ:DNDN - 6.35) has been on the bullish trading radar lately, according to data pulled from the International Securities Exchange (ISE), Chicago Board Options Exchange (CBOE), and NASDAQ OMX PHLX (PHLX). In fact, the equity sports a 50-day call/put volume ratio of 7.01, confirming traders have bought to open seven calls for every put during the last 10 weeks. This ratio is just 7 percentage points shy of a yearly peak, meaning speculators have been snatching up calls over puts at a near annual-high clip.

This campaign for bullish options over bearish is evident in today's session, as well. Roughly 16,000 calls have crossed the tape so far – nearly triple the stock's expected intraday call volume, and almost seven times the number of puts exchanged. Weekly speculators have zeroed in on the 1/25 6.50-strike call, which has seen more than 4,400 contracts traded at a volume-weighted average price (VWAP) of $0.12.

Digging deeper into the data, it looks as though the majority of these near-the-money calls changed hands at the ask price, implying they were bought. This strike presently holds open interest of fewer than 1,300 contracts, and implied volatility has spiked more than 21 percentage points during the course of the session -- both indicators of buy-to-open activity. In other words, traders are expecting DNDN to rise north of $6.62 (strike price plus the VWAP) by tomorrow's close, which is when these weekly options expire. This reflects a 4.3% increase over the stock's current perch.

Technically speaking, the biotech firm has advanced almost 20% year-to-date, and has bested the broader S&P 500 Index (SPX) by more than 47 percentage points during the past three months. Furthermore, DNDN is on pace to close January atop its 10-month moving average -- a trendline that has eluded the stock since July 2011. Still, should the equity fail to conquer the aforementioned breakeven rail, the most today's bulls risk losing is the initial premium paid.